The present invention relates to an improved sorbent capsule of the type which is packaged with pharmaceuticals.
By way of background, sorbent cartridges such as disclosed in U.S. U.S. Pat. Nos. 4,093,105, 4,772,300 and 5,503,662 have been inserted with pharmaceuticals for the purpose of preventing their deterioration from moisture. However, the foregoing cartridges had a moisture-impermeable plastic cylindrical shell and separate porous end caps, and they were filled with uncompressed granular sorbent. Thus, their production cost included the cost of fabrication of their shells and end caps, and the labor of filling and assembling them. In addition, since their contents were uncompressed granular sorbents, their sorbent capacity was limited to their granular volume. Also, the end caps of U.S. Pat. No. 4,093,105 were screens through which objectionable dusting could occur. Also, European Patent 0387604 disclosed a pressed desiccant tablet having a binder of polyvinylpyrrolidone and having a sprayed methylhydroxypropylcellulose coating. However, the binder was water-soluble and the coating was water-based. The water-based coating could potentially degrade the pressed desiccant during a pan-coating process.